Field of the Invention
The present invention relates generally to the field of construction of buildings and structures. More particularly, the present invention relates to a construction panel and system that can be used to provide structures with superior shear load carrying capability.
Related Art
The vast majority of structures constructed today are subject to loading conditions that require walls of the structure to adequately carry lateral loads from such forces as wind, seismic activity, and some gravitational loads. As a result, many wood frame buildings use “shear walls” to resist lateral loads. A shear wall is typically formed by the application of one or more types of sheeting, such as plywood, fiberboard, particleboard, and/or drywall (gypsum board), to the inside or outside (or both) sides of a dimensional lumber (or other framing material) wall frame. The sheeting is fastened to the wall frame at many points to create a shear wall. The sheeted shear wall is beneficial, and in some applications even necessary, to transmit lateral forces acting upon the frame of the structure to the foundation of the structure.
In a typical application, a shear wall is formed while a building or structure is erected. In applications where wooden framing is utilized, dimensional lumber such as “2×4s,” “2×6s,” 2×8s,” etc., are first used to create a framework of mostly vertical components that serve to carry loads vertically to the foundation of the structure. Typically, nails are used to secure the components to one another while the wall is erected. While such a system has proven, over many years, to effectively provide the load-carrying capability necessary to withstand vertical loading experienced during normal use, such systems are not well suited to carry lateral loads applied by wind, seismic activity and the like.
As such, most building codes require the addition of sheeting to the outer (or inner) face of the frame components. The shear panels, which can be as simple as plywood sheets, must be nailed or screwed in specified patterns to meet code. It has been found, however, that when walls constructed in such a manner fail under wind or seismic loading conditions, failure is often initiated at the locations where the shear panels were nailed or screwed to the underlying framework. Thus, while this conventional manner of providing shear strength to walls is effective in some cases, failure of the system has been experienced in others. Also, the fact that such sheeting is required often considerably increases the cost of the walls of the structure, as well as the time required to erect the walls.